<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <script>
        let persons = [
            {
                username: '张飞',
                sex: '男',
                salary: 50000
            },
            {
                username: '关羽',
                sex: '男',
                salary: 60000
            }
        ];
        var newPersons = [];
        persons.forEach(function(val,index){
            var a={}
            for(var k in val){
                if (k=="salary") {
                    a[k]=val[k]+2000
                } else {
                    a[k]=val[k]
                }
            }
            newPersons.push(a)
        })
        console.log(newPersons);
    </script>
</body>

</html>